It is proposed to develop, test physically and evaluate clinically a new fast film/screen system for performing mammography with radiation doses lower than those employed at present, without compromising the quality of the radiographic images. The physical performance in terms of speed, resolution, contrast and noise will be measured for existing low dose systems. Combinations of new or experimental screens and available blue- or green-sensitive films, will be tested. Experimental screens will be developed from new phosphor materials with efficient x-ray absorption and high light output using either sputtering or evaporation techniques to maximize the packing density on the screens. It is planned to test clinical efficacy of these screens in the diagnosis of early mammary carcinoma.